1. Field of the Invention
The invention relates to a non-volatile memory and a manufacturing method thereof. More particularly, the invention relates to a non-volatile memory capable of preventing second bit effect and program disturbance and a manufacturing method thereof.
2. Description of Related Art
Having the advantage of saving the stored data after the power is turned off, non-volatile memory is required in many electrical appliances for the normal operation of electrical appliances. Specifically, flash memory is a memory device widely adopted in personal computers and electronic apparatuses as flash memory is capable of performing operations such as data storage, reading, and erasing.
Nitride-based flash memory is one of the conventional non-volatile memories. In nitride-based flash memory, a charge capture structure constituted by oxide layer-nitride layer-oxide layer (that is, the well-known ONO layer) is capable of storing 2-bit data. Generally, 2-bit data is stored respectively on the left side (that is, the left bit) or the right side (that is, the right bit) of the nitride layer in the charge capture structure.
However, the nitride-based flash memory includes the second bit effect. That is, the left bit is affected by the right bit when being read, or the right bit is affected by the left bit when being read. In addition, with the gradual reduction of memory size, the length of the channel is also reduced, such that the second bit effect is further worsened. The operation window and device performance of the memory is affected as a result. Moreover, the distances between the devices are also shortened as the size of the memory is reduced. Thus, the program disturbance may also occur when the adjacent memory is programmed.